A transformerless high boost DC-DC converter for use in medium / high voltage applications

The proliferation of distributed energy resources has prompted interest in the expansion of DC power systems. One critical technological limitation that hinders this expansion is the absence of high step-down and high step-up DC converters for interconnecting DC systems. This work attempts to address the latter of these limitations. This paper presents a new transformerless high boost DC-DC converter intended for use as an interconnect between DC systems. With a conversion ratio of 1:10, the converter offers significantly higher boost ratio than the conventional non-isolated boost converter. It is designed to operate at medium to high voltage (>; 1kV), and provides high voltage dc/dc gain (>;5). Based on a current fed resonant topology, the design is well matched to available IGBT switch technology that enables use of relatively high switching frequencies yet accommodates the IGBTs inability to provide reverse blocking functionality. An advanced steady state model suitable for analysis of this converter is presented together with an experimental evaluation of the converter.